A contactor is an electrically controlled switch device used for switching an electric power or control circuit of an electrical load device. Such a contactor comprises a contacting unit, an actuating unit and an enclosure for housing the actuating unit and the contacting unit. The contacting unit includes a movable contact and a stationary contact, both are for carrying current when a contact is made between them. The actuating unit is for operating the movable contact for electrical connection or disconnection.
An auxiliary contact block may include a plurality of contacting units. An auxiliary contact block may be added to a contactor when additional contacts or additional functions are required, for example, to indicate an operation status of a contactor or, to use it as a safety purpose for two contactors to prevent them from being closed simultaneously, otherwise a short circuit occurs. To connect an auxiliary contact block to a contactor, an auxiliary contact block is traditionally secured by screws to the contactor. Therefore, tools are needed for making such a connection.
A patent EP0831569B discloses an auxiliary switch including a tool free connection mechanism. The auxiliary switch comprises an actuation nipple extending out from a first side-wall of the switch housing and for coupling to a movable switch element of an additional auxiliary switch or electromagnetic switch device. Two snap hooks or catches protrude out from the first side-wall of the switch housing and adjoin pressure pieces disposed on an opposite-facing narrow third side-walls, where the snap hooks is adapted to be engaged into recesses of a housing wall of a further auxiliary switch or switch device. The invention enables an operator to connect the auxiliary switch to a lateral wall of an additional auxiliary switch or electromagnetic switch device without using tools. However, when a connection is performed in a limited space, for example, in a cabinet, it might be difficult to reach the snap hooks in order to remove the auxiliary switch from the electromagnetic switch device, because this needs spaces in both sides of the auxiliary switch.